JPH11183765A - Pipe aggregate cable and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily take out a pipe on an inner layer in an intermediate part of a cable. SOLUTION: The pipe aggregate cable is constituted of binding plural pipes 1 each of which is a plastic pipe having a hole 1b on its center and a modified cross section other than a circle on its outer periphery so that the modified state is spirally formed around a center axis in the longitudinal direction of the pipe and covering the outside of the bound pipes 1 with a coat 4. As an example of the modified cross section on the outer periphery of the pipe, projected stripes 1a are formed on the outer periphery of the pipe, the outer periphery of the pipe is formed like an elliptic cross section, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe assembly cable in which pipes mainly used for pressure-feeding a linear body such as an optical fiber by compressed air.

[0002]

2. Description of the Related Art As a method of laying an optical fiber, an optical fiber coated with a single core or a plurality of cores collectively in a pipe of a so-called pipe aggregate cable in which a plurality of plastic pipes are aggregated is added with air or the like. There is a method in which a pressurized gas is fed by pressurizing gas to lay the container.

In the method of laying an optical fiber by pressurized gas pressure feeding, a force that travels in the longitudinal direction of the optical fiber is generated by using a pressure gradient of the gas and the fiber is inserted into the optical fiber, so that an excessive tension is applied to the optical fiber. No laying is possible. Further, a tensile member such as a steel wire is not required for the optical fiber, and the protection structure of the optical fiber can be simplified. Furthermore, it is possible to lay only a cable in which the pipe is combined with a pipe collective cable or a communication line, a power line, and the like, and to lay an optical fiber in the pipe by pressure feeding at a necessary time as needed. It has the effect of reducing the initial investment of equipment and is often used as a useful construction method.

[0004] The pipe for the pipe assembly cable provided in this pressurized gas pressure feeding method is made of plastic such as polyethylene and has an inner diameter of about 2 to 8 mm and a wall thickness of about 0.7 to 0.7 mm.
1.5mm circular pipe with inner diameter of 4-6m
m, an outer diameter of 6 to 8 mm, and a wall thickness of 1 mm are often used.

FIG. 4 is a cross-sectional view showing an example of the pipe assembly cable. The pipe assembly cable 15 is composed of a plurality of pipes 11 made of plastic such as polyethylene having a circular cross section in the transverse direction. , And are assembled by twisting together and applying the upper winding 13 and the coating 14. Incidentally, plastic yarns or the like are used as the inclusions, and the coating is usually mainly composed of a plastic such as polyethylene or vinyl chloride resin. When the pipe assembly cable is buried underground, a metal tape or the like may be combined with the covering plastic.

In this pipe aggregated cable, six pipes 11 are arranged as a first layer around a center pipe 11 and twisted together with an inclusion 12 at an appropriate pitch, and around the pipes, 12 pipes 11 are formed as a second layer. Are lined up with inclusions 12
And at the appropriate pitch. Therefore, even if the coating is removed over a length of about 20 to 50 cm at the longitudinal middle portion of the pipe assembly cable and only the desired pipe is to be taken out therefrom, the outer layer pipe can be taken out, but the center or inner layer pipe cannot be taken out. Since it is difficult to make a gap between the pipes, they cannot be taken out.

[0007]

In a pipe assembly cable according to the prior art, a plurality of pipes made of plastic having a circular cross section are formed into a multilayer structure and twisted so that there is almost no gap between adjacent pipes. Therefore, even if an attempt is made to take out only a desired pipe for an intermediate branch or the like at an intermediate portion in the longitudinal direction of the pipe assembly cable, if the pipe is in the inner layer, a gap is formed in the outer layer pipe. There is a problem that it cannot be taken out because it is difficult to make. SUMMARY OF THE INVENTION The present invention provides a pipe aggregate cable from which a pipe in an inner layer can be easily taken out, and a method for manufacturing the same.

[0008]

SUMMARY OF THE INVENTION A pipe assembly cable according to the present invention is a pipe assembly cable in which a plurality of pipes mainly used for inserting a linear body through compressed air are assembled. A pipe made of plastic with a hole and an outer peripheral surface with an irregular cross section other than a circular shape. The irregular shape of the outer peripheral surface is formed spirally around a central axis with respect to the longitudinal direction of the pipe. In addition, a plurality of the pipes are bundled and the outer side thereof is covered.

In order to make the outer peripheral surface of the pipe an irregular shape other than a circular shape, it is practical to provide a projection on the outer peripheral surface of the pipe or to make the outer peripheral surface of the pipe have an elliptical cross-sectional shape.

In order to make the deformed state helical with respect to the longitudinal direction of the pipe, a method of extruding a pipe made of plastic having an irregular outer cross section in a straight line, and then twisting the pipe in the longitudinal direction, In the extrusion molding, any method of extruding a pipe in which a deformed state is formed in a helical shape in a longitudinal direction by a rotating die attached to the extruder can be adopted.

[0011] A pipe bundled cable in which a plurality of bundles of pipes having an irregular cross-section whose outer peripheral surface is not circular as described above and whose deformed state is helical with respect to a central axis in the longitudinal direction is bundled into a plurality of bundles. Since the adjacently arranged pipes are arranged in such a manner that portions of the deformed maximum outer diameters are in contact with each other, the pipes are gathered such that the interval between the central axes of the adjacent pipes is substantially equal to the maximum outer diameter of the deformed cross section.

At the intermediate portion of the pipe assembly cable, the covering and the upper winding are removed to expose the pipe portion, and a finger is inserted into one portion between the adjacent pipes to spread the pipe. Since the rigidity is lower than that of metal etc., the twisted state of the pipe is slightly shifted in the longitudinal direction between the other pipes under the pressure of the pressed pipe, and the large part of the deformed outer periphery is By being engaged with the small portion, the interval between the central axes of the pipes is reduced, and the interval between the pipes to be expanded can be increased.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a perspective view showing an example of a pipe used in a pipe assembly cable of the present invention before twisting, and FIG. 1B is a view showing the pipe after twisting. FIG. 1C is a perspective view, and FIG. 1C is a cross-sectional view of a pipe assembly cable using the pipe. In FIG. 1, 1 is a pipe made of plastic such as polyethylene, 1a is a protrusion formed on the outer peripheral surface of the pipe, 3 is an upper winding made of tape such as plastic, and 4 is a coating made of plastic such as polyethylene and vinyl chloride resin. It is.

The inner diameter of the pipe is 2 to 8 mm, the thickness is 0.7 to 1.5 mm, and the height of the projection is 0.25 to 4.0.
mm, when the inner diameter is 4 mm and the outer diameter is 6 mm, the height of the protrusion is preferably about 1.5 mm. Further, FIG. 1 shows two examples of the protrusions formed on the outer periphery of the pipe, but one or three or more protrusions may be used.

FIG. 2A is a perspective view showing another example of a pipe used for the pipe assembly cable of the present invention before twisting, and FIG. 2B is a perspective view showing the pipe after twisting. FIG. 2C is a cross-sectional view of a pipe assembly cable using the pipe. In FIG. 2, reference numeral 2 denotes a pipe made of plastic such as polyethylene, and its outer peripheral surface has an elliptical cross section. Reference numeral 3 denotes an upper winding made of a tape such as plastic, and reference numeral 4 denotes a coating made of a plastic such as polyethylene or vinyl chloride resin. The inner diameter of the pipe is 2-8m
m, the minor axis × major axis of the outer peripheral ellipse is 3.5 × 4.0 to 11 ×
12 mm, the major axis / minor axis is about 1.05 to 1.8, and in the case of a pipe having an inner diameter of 4 mm, the ellipse on the outer periphery has a minor axis of 6.
0 mm and a long diameter of about 7.5 mm are good.

In the example shown in FIGS. 1 and 2, the pipe 1 or 2 is manufactured by a method in which the pipe 1 or 2 is extruded in a straight line, twisted in the longitudinal direction to make the deformed state spiral, and assembled into a bundle. Although an example was shown, a method in which a pipe formed in a spiral shape in a deformed state in the longitudinal direction is extruded by a rotating die attached to an extruder, as shown in FIG.
A pipe similar to that of FIG. 2B can be manufactured.

1 and 2, the bundled pipe 2 is used.
Interstices such as plastic yarns may be inserted between the gaps as necessary. Further, in the case of a pipe aggregate cable used for underground burial or the like, a metal tape or the like may be combined with a plastic covering.

As a method for bundling the pipes 1 or 2, a plurality of pipes may be simply bundled together and wound up, but in order to facilitate identification of the plurality of pipes. It is better to twist the layers together and form an upper winding so that the relative arrangement of the pipes is constant in the longitudinal direction, and the interval between the pipes at the time of assembly is also about the same as the maximum outer diameter of the pipe Desirable for ease. Also,
In this case, it is preferable that the pitch is slightly changed or the twisting direction is changed for each layer so that the pipe does not fall between the layers. The twisting pitch of each layer is 100
It is selected from the range of about 2000 mm depending on the twisted outer diameter.

The pipe assembly cable of the present invention produced as described above removes the covering and the upper winding by about 20 to 50 cm to expose the pipe portion, and puts a finger in one place between adjacent pipes and spreads it. Between the other pipes near the pipe that received the pressure of the pressed pipe, the protrusions on the pipe surface or the portion of the major axis of the ellipse are slightly shifted in the longitudinal direction, and are pushed into the portion without the projection or the minor axis of the ellipse. The distance between the parts where the fingers are inserted can be widened.

At this time, even if inclusions are contained, since the inclusions are made of a soft material such as a plastic yarn,
When the pipe is pushed, it enters the irregularly shaped short diameter portion of the pipe and is compressed, so that there is no hindrance to pushing and expanding the pipe. Note that FIG. 3 is a diagram showing a state in which the outer layer and the one-layer pipe of the pipe-assembled cable of FIG. 1 (C) are to be pushed out to take out the central pipe, and it is possible to take out one central pipe. Two layers and one as much as possible
It shows that the spacing of the pipes in the layers can be increased.

[0021]

The pipe assembly cable of the present invention comprises a bundle of a plurality of pipes each having an outer peripheral surface having an irregular cross section and an irregular shape spirally formed around a central axis in the longitudinal direction of the pipe. Because it is provided with a coating on the outside,
Dozens of cm for the middle branch at the middle of the cable
By removing the coating of the pipe and exposing the pipe, and expanding the gap between the pipes, the deformed part of the outer peripheral surface of the pipe shifts and the part with the maximum outer diameter of the deformed bites into the part of the deformed minor diameter. It is possible to take out an arbitrary pipe even if it is an inner layer pipe.

The pipe used in the pipe assembly cable of the present invention is provided with a hole having a circular cross section along the center axis of the pipe, and the shape of the hole is not different from that of the conventional pipe assembly cable. In the same manner as in the technology, it is possible to lay a linear body such as an optical fiber under pressure by compressed air in a pipe.

Further, in order to make the deformed state spiral in the longitudinal direction of the pipe, a pipe made of plastic having a deformed outer peripheral surface is extruded in a straight line and then twisted in the longitudinal direction. The outer peripheral surface is deformed and the deformed state is changed by adopting any one of a method and a method of extruding a pipe in which a deformed state is formed in a spiral shape in a longitudinal direction by a rotating die attached to an extruder during extrusion molding. It is possible to easily manufacture a pipe spiraled in the longitudinal direction.

[Brief description of the drawings]

FIG. 1A is a perspective view showing an example of a pipe used for a pipe assembly cable of the present invention before twisting, and FIG. 1B is a perspective view showing the pipe after twisting. (C) is a cross-sectional view of a pipe assembly cable using the pipe.

FIG. 2A is a perspective view showing another example of a pipe used in the pipe assembly cable of the present invention before twisting, and FIG.
FIG. 3 is a perspective view showing the pipe after twisting, and FIG. 3C is a transverse sectional view of a pipe assembly cable using the pipe.

FIG. 3 is a cross-sectional view showing a state where a space between pipes is expanded using the pipe aggregate cable of FIG. 1 (C).

FIG. 4 is a cross-sectional view of a conventional pipe aggregate cable.

[Explanation of symbols]

 1, 2: pipe 1a: protrusion 3: upper winding 4: coating

Claims (5)

[Claims] 1. A pipe assembly cable in which a plurality of pipes are assembled, wherein the pipe is a pipe made of plastic having a hole in the center and an outer peripheral surface having a modified cross section other than a circular shape. The deformed state is formed spirally around the central axis of the pipe with respect to the longitudinal direction of the pipe, and a plurality of the pipes are bundled and a coating is applied to the outside thereof. . 2. The pipe assembly cable according to claim 1, wherein the pipe has an irregular cross-section due to a projection provided on an outer peripheral surface. 3. The pipe aggregate cable according to claim 1, wherein the pipe has an irregular cross-section due to an elliptical outer peripheral surface. 4. A method of manufacturing a pipe assembly cable in which a plurality of pipes are assembled, wherein a pipe made of plastic having a hole at the center and an outer peripheral surface having an irregular cross-section other than a circular shape is extruded in a straight line. Manufacturing a pipe aggregated cable by twisting a pipe around its central axis in the longitudinal direction to make the irregular cross section of the outer peripheral surface spiral, then bundling a plurality of the pipes, and coating the outside thereof; Method. 5. A method of manufacturing a pipe assembly cable in which a plurality of pipes are assembled, wherein a pipe made of plastic having a hole at the center and an outer peripheral surface having a modified cross section other than a circular shape is pushed from a rotary die attached to an extruder. A method of manufacturing a pipe aggregate cable, comprising forming a pipe in which the shape of the irregular cross section of the outer peripheral surface of the pipe is formed into a spiral shape, bundling a plurality of the pipes, and coating the outside thereof.